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Such a contradiction has led to hundreds of wrongful convictions across the country, according to cases where DNA evidence has exonerated the accused.

“About a quarter of those were convicted on eyewitness testimony, and little else,” said Lawrence Wrightsman, a professor emeritus of psychology at the University of Kansas. Wrightsman has studied and written extensively on psychology and the law.

In Kansas, judges may instruct jurors that they may gauge credibility on several factors, including “the degree of certainty demonstrated by the witness at the time of any identification.”

Such certainty and confidence tend to influence jurors, studies show.

“A victim or a witness takes the stand, and he or she are very sincere and often times very explicit and very confident, and all those are qualities people assume go with accuracy. But they don’t,” Wrightsman said.

“You can find confident people who are not accurate. And you can find people who are hesitant, who are just careful people, and they are very accurate.”

Mitchell’s trial in 2007 focused on a witness who was “100 percent” confident. Based on that testimony, the Sedgwick County jury convicted Mitchell of aggravated robbery and a judge sentenced him to nearly 7 years in prison.

Mitchell had been charged with a home invasion in November 2006. A man said someone kicked in his door, punched him in the eye and took $70 from his pockets. The man gave a vague description and later picked Mitchell out of a photo lineup.

On the photo lineup, the witness scribbled that he was “100 percent” certain Mitchell was the robber.

The witness also said he was temporarily blinded after being punched in the face, that the incident lasted just a couple of minutes, and that he described his assailant as being much taller and heavier than Mitchell, his lawyers argued.

The jury was given the standard instruction on eyewitness testimony, over the objections of the defense.

“If that factor has been rejected as a poor indicator of reliability, it should be removed from the instructions guiding juries,” appellate public defender Ryan Eddinger argued in his filings to the Supreme Court.

Mitchell is asking for a new trial.

Prosecutors say the verdict would have been the same no matter what the jury was told. The man said he knew his attacker and had even let him stay in his apartment, court records show.

“The cautionary eyewitness identification was not necessary in this case,” wrote Julie Koon of the Sedgwick County District Attorney’s office in her legal arguments.

Other states are also re-evaluating eyewitness testimony.

Three years ago, the New York Supreme Court ruled that judges must allow qualified experts to testify on reliability when cases hinge on eyewitness testimony.

In Kansas, judges rarely allow such experts, said Michael Kaye, law professor at Washburn University, and that makes the jury instructions more important.

“Without experts, all you have is the jury instructions to guide them,” Kaye said.

“The public needs to know that eyewitnesses are not always right,” Kaye added. “That the court is willing to consider science and other factors shows progressive thinking.”

Wrightsman said witnesses don’t mean to make mistakes.

“It’s not anything purposeful or malicious,” he said. “People are just wrong sometimes.”